Tire molding drum

Abstract

To make it possible to automatically join tread ends of a tread member protruding from a belt member using a pressure device, when joining a tip end and a rear end of the tread member in a circumferential direction.SOLUTION: A tire molding drum 4 molds a ring-shaped tire member on an outer peripheral surface of a drum 40, and the drum 40 includes: a first segment 31 on which a tip end 22F of a tread member 22 is positioned when wound; and a second segment 32 on which a rear end 22R of the tread member 22 is positioned. The first segment 31 and the second segment 32 each have a central segment 41, 42 around which a belt member 24 is wound, and an end segment 51, 52. The end segment 51 has a needle-attached segment 51A having a plurality of needles 54 that are inserted into the tip end 22F of the tread member 22 and a step part 55 that supports the tread member 22, and a needle-less segment 51B. The end segment 52 and the needle-less segment 51B support a lower surface of the tread member 22.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a tire molding drum.

Background Art

[0002] A drum for manufacturing a tire belt and tread has been disclosed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a drum for winding a belt member and a tread member in a conventional molding machine for truck and bus (TBR) tires, in order to be able to expand and contract corresponding to different tire sizes, a plurality of segments are arranged in the circumferential direction. And the surface of this segment has a flat shape in the cross section in the drum axial direction. A plurality of layers of belt members are wound around this drum, and a tread member is wound around the outside thereof. In the axial direction of the drum, the width of the tread member is larger than the width of the belt member, and both ends in the width direction of the tread member protrude outside the belt end, that is, in a region not supported by the belt member. In particular, in TBR tires, since the number of belt members is larger than that of passenger car (PSR) tires, the gap between the tread member protruding from the belt end and the drum surface becomes larger.

[0005] Further, the tread member is composed of a combination of a plurality of rubber types, and the rubber swelling has a complicated shape for each part. For this reason, the shrinkage conditions of the tread member differ depending on the part. Also, the shrinkage conditions of the tread member differ depending on its size.

[0006] The tread member is cut to a predetermined length and wound around a drum. At this time, the front end portion and the rear end portion in the circumferential direction of the tread member are pressed and joined by a pressing device in a state of being overlapped with each other on the drum. At this time, since there are a gap between the tread end and the drum surface and differences in the shrinkage conditions of each part of the tread member, it has been difficult to control the position of the rear end portion in the circumferential direction at the tread end to coincide with the position of the front end portion.

[0007] An object of the present invention is to enable not only the portion of the tread member supported by the belt member but also the tread ends protruding from the belt member to be automatically joined by a pressing device when joining the front end portion and the rear end portion in the circumferential direction of the tread member.

Means for Solving the Problems

[0008] The tire molding drum according to the first aspect is a tire molding drum for molding a ring-shaped tire member by winding a tire material around the outer peripheral surface of a substantially cylindrical drum. The drum has a plurality of segments divided in the circumferential direction. The segments include a first segment where the tip of the tread member as the tire material is disposed during winding, and a second segment where the rear end of the tread member is disposed during winding. The first segment and the second segment each have a central segment located on the central side in the axial direction of the drum around which the belt member as the tire material is wound, and an end segment adjacent to the outside of the central segment in the axial direction. The end segment in the first segment has a plurality of needles that extend from the radially inner side to the radially outer side and are inserted into the tip of the tread member when the tread member is wound around the drum, and a stepped portion provided integrally with the needles to support the tread member when the needles extend, and a segment without needles having no needles. The end segment in the second segment and the segment without needles in the first segment are configured to support the lower surface of the tread member when the tread member is wound around the drum.

[0009] This tire molding drum has a first segment where the tip of the tread member is disposed during winding, and a second segment where the rear end of the tread member is disposed during winding. The first segment and the second segment each have a central segment and an end segment. The belt member is wound around the central segment. The tread member is wound on top of the belt member. The width of the tread member is larger than the width of the belt member, and the tread ends protrude from the belt member.

[0010] The end segment in the first segment has a segment with needles and a segment without needles. When the tread member is wound around the drum, a plurality of needles extend from the segment with needles from the radially inner side to the radially outer side and are inserted into the tip of the tread end. Thereby, the position of the tip of the tread end protruding from the belt member in the tread member can be stabilized.

[0011] Also, when the tread member is wound around the drum, the end segment in the second segment and the segment without needles in the first segment support the lower surface of the tread member. Thereby, when the rear end portion of the tread end in the tread member is pressed by a pressing device and overlapped and joined with the front end portion of the tread end, it becomes easy to stretch the rear end portion of the tread end toward the front end portion side. Thereby, the rear end portion of the tread end can be appropriately overlapped and pressed against the front end portion, and both can be joined with high precision.

[0012] A second aspect is the tire molding drum according to the first aspect, wherein the position of the stepped portion of the needle, the position of the segment without needles in the first segment, and the position of the end segment in the second segment when the tread member is wound around the drum correspond to the position of the outermost surface of the belt member.

[0013] In this tire molding drum, when the tread member is wound around the drum, the position of the stepped portion of the needle, the position of the segment without needles in the first segment, and the position of the end segment in the second segment correspond to the position of the outermost surface of the belt member. Therefore, the tread end protruding from the belt member when the tread member is wound around the drum can be supported by the stepped portion of the needle, the segment without needles in the first segment, and the end segment of the second segment. Thereby, when the rear end portion of the tread end in the tread member is pressed by a pressing device and overlapped and joined with the front end portion of the tread end, it is possible to start pressing the rear end portion of the tread end from the position of the second segment far from the rear end portion of the tread end. Thereby, the rear end portion of the tread end can be further stretched.

[0014] In the third aspect, in the tire molding drum according to the first aspect or the second aspect, the position of the tip of the needle in the radial direction of the drum with the needle extended is different depending on the circumferential position of the drum.

[0015] In this tire molding drum, since the position of the tip of the needle in the radial direction of the drum with the needle extended is different depending on the circumferential position of the drum, the needle can be inserted along the cross-sectional shape of the tip of the tread member in the circumferential direction of the drum. Also, thereby, while securing the insertion length of the needle, it is possible to suppress the needle from penetrating the tip of the tread member. For this reason, the position and shape of the tip of the tread member can be stabilized.

[0016] In the fourth aspect, in the tire molding drum according to any one of the first to third aspects, the end segment is movable in the axial direction of the drum in accordance with the width of the central segment in the axial direction of the drum.

[0017] In this tire molding drum, since the end segment is movable in the axial direction of the drum in accordance with the width of the central segment in the axial direction of the drum, it is possible to correspond to various tire sizes and belt members of various widths.

Advantages of the Invention

[0018] According to the present invention, when joining the front end portion and the rear end portion in the circumferential direction of the tread member, not only the portion of the tread member supported by the belt member but also the tread ends protruding from the belt member can be automatically joined by the pressing device.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Components denoted by the same reference numerals in each drawing mean the same or similar components. In the embodiments described below, duplicate descriptions and reference numerals may be omitted. Also, the drawings used in the following description are all schematic, and the dimensional relationships between the respective elements shown in the drawings, the ratios of the respective elements, etc. do not necessarily match the actual ones. Also, the dimensional relationships between the respective elements and the ratios of the respective elements do not necessarily match even between multiple drawings.

[0021] In the drawings, the direction of arrow C indicates the tire circumferential direction, the direction of arrow R indicates the drum diameter direction, and the direction of arrow W indicates the drum width direction. The drum diameter direction means the direction perpendicular to the drum rotation axis (not shown).

[0022] [Tire forming device] In FIG. 1, the tire forming device 1 includes a supply device 3 for supplying a tire material 2, a tire forming drum 4 on which the tire material 2 is disposed, a pressing device 10 for the tire material 2, and a control device (not shown). The tire forming device 1 is controlled by the control device to perform a tire forming operation, and the pressing device 10 presses the tire material 2 from the outer circumference.

[0023] The supply device 3 has a conveying device 5 for conveying the tire material 2, and supplies the tire material 2 to the tire forming drum 4 in accordance with the rotation of the tire forming drum 4. The tire material 2 is wound around the outer circumference of the tire forming drum 4 and is disposed at a predetermined position on the outer circumference of the tire forming drum 4, and is formed into a cylindrical shape by the tire forming drum 4. During the arrangement of the tire material 2 on the tire forming drum 4 or after the arrangement of the tire material 2 on the tire forming drum 4, the pressing device 10 presses the tire material 2 toward the tire forming drum 4.

[0024] (Pressing device) As shown in FIGS. 1 and 2, the pressing device 10 includes a shaft member 20 extending linearly, a pair of holding members 11 that hold both ends of the shaft member 20, a plurality of rotatable pressing rolls 12 that surround the shaft member 20, and a moving device 13 that moves the shaft member 20. The shaft member 20 is a non-rotating core member disposed inside the plurality of pressing rolls 12 and penetrates the plurality of pressing rolls 12 in the axial direction. The plurality of pressing rolls 12 are arranged in the axial direction of the shaft member 20 and are adjacent to each other in order around the shaft member 20. The pair of holding members 11 connect the shaft member 20 to the moving device 13.

[0025] The moving device 13 is, for example, a piston-cylinder mechanism, and moves the shaft member 20 in the radial direction of the tire molding drum 4 together with a plurality of pressing rolls 12. By the moving device 13, the shaft member 20 approaches or moves away from the tire molding drum 4. Further, by the moving device 13, the plurality of pressing rolls 12 move between a position in contact with the tire material 2 and a position away from the tire material 2. The plurality of pressing rolls 12 are annular pressing members that rotate in contact with the tire material 2 and press the tire material 2 in a predetermined pressing direction P.

[0026] When the tire material 2 is pressed, the shaft member 20 is arranged along the tire material 2 at the pressing position, and the plurality of pressing rolls 12 are arranged in parallel along the outer peripheral surface of the tire material 2. Here, the shaft member 20 is arranged parallel to the axial direction of the tire molding drum 4. At a predetermined position in the circumferential direction of the tire molding drum 4, the plurality of pressing rolls 12 press the entire width direction of the tire material 2. As the tire molding drum 4 rotates, the plurality of pressing rolls 12 move relatively in the circumferential direction of the tire molding drum 4 and press the entire circumferential direction of the tire material 2. At this time, the pressing device 10 presses the plurality of pressing rolls 12 in the pressing direction P of the tire material 2 respectively by a pressing mechanism (not shown) provided inside the plurality of pressing rolls 12. Note that the pressing direction P of the tire material 2 is the direction of the pressure applied from the pressing roll 12 to the tire material 2, and the width direction of the tire material 2 is a direction parallel to the axial direction of the tire molding drum 4.

[0027] The plurality of pressing rolls 12 operate independently. By the pressing device 10, the plurality of pressing rolls 12 are displaced in a predetermined direction around the shaft member 20 while surrounding the shaft member 20. Here, the plurality of pressing rolls 12 are displaced independently of each other in the pressing direction P of the tire material 2 and the direction opposite to the pressing direction P (for example, the radial direction R). Further, the plurality of pressing rolls 12 are each pressed against the tire material 2 to press the tire material 2 in the pressing direction P.

[0028] (Tire molding drum) In FIGS. 3 to 10, the tire molding drum 4 according to the present embodiment is an apparatus for molding a ring-shaped tire member by winding a tire material 2 around the outer peripheral surface of a substantially cylindrical drum. The tire molding drum 4 has a rotating device (not shown) having a motor or the like, and the drum 40 rotates at a predetermined speed about its axis by the rotating device.

[0029] The drum 40 has a plurality of segments divided in the circumferential direction thereof. As the segments, a first segment 31 where the tip portion 22F (see FIGS. 7 and 8) of the tread member 22 as the tire material 2 is disposed during winding, and a second segment 32 where the rear end portion 22R (see FIGS. 7 and 8) of the tread member 22 is disposed during winding are provided. The first segment 31 and the second segment 32 each have central segments 41, 42 located on the central side in the axial direction of the drum 40 around which a belt member 24 (FIG. 5) as the tire material 2 is wound, and end segments 51, 52 adjacent to the outside of the central segments 41, 42 in the axial direction, respectively. The central segments 41, 42 are replaceable, and the end segments 51, 52 are movable in the axial direction in accordance with the width of the central segments 41, 42 in the axial direction of the drum 40.

[0030] As shown in FIGS. 4 to 8, the end segment 51 in the first segment 31 has a segmented segment 51A with needles and a segmented segment 51B without needles. The segmented segment 51A with needles has a plurality of needles 54 and a step portion 55 provided integrally with the needles 54 and supporting the tread member 22 when the needles 54 extend. As an example, the step portion 55 is the upper end of the large-diameter portion, and the lower end of the large-diameter portion is fixed to a base portion 58 described later. The needles 54 are smaller in diameter than the large-diameter portion, and the tips are formed sharp. The needles 54 extend from the radially inner side to the radially outer side when the tread member 22 is wound around the drum 40 and are inserted into the tip portion 22F of the tread member 22. A large number of needles 54 are provided in one end segment 51. This is to stabilize the position and shape of the tip portion 22F of the tread member 22 by the needles 54.

[0031] The needle 54 is erected, for example, on a plate-shaped base 58. The base 58 is supported by a guide 56 extending in the axial direction of the drum 40. The guide 56 is movable in the radial direction of the drum 40, for example, by the expansion and contraction of a cylinder device 57. When the guide 56 moves, the base 58 on which the needle 54 is erected also moves in the radial direction of the drum 40.

[0032] The segment 51A with a needle has a needle cover 60 having a number of through-holes 60A corresponding to the needles 54. The needle cover 60 is supported by a guide 62 extending in the axial direction of the drum 40, for example, and is movable together with the needles 54 and the base 58 when moving the end segment 52 in the axial direction of the drum 40. Note that no cylinder device is provided on the guide 62, and it is configured not to move in the radial direction of the drum 40 except when the entire drum 40 expands and contracts. In other words, the needle cover 60 does not move when the needles 54 advance and retract. Thus, when the base 58 of the needle 54 moves in the radial direction of the drum 40 due to the expansion and contraction of the cylinder device 57, the needle 54 advances and retracts between a state of being stored inside the through-hole 56A and a state of protruding outside the through-hole 56A.

[0033] As shown in FIGS. 7 and 8, the position of the tip of the needle 54 in the radial direction of the drum 40 in the state where the needle 54 extends is different depending on the circumferential position of the drum 40. Specifically, the thickness of the tip portion 22F of the tread member 22 is formed to taper in the circumferential cross-section. Corresponding to this shape, the needle 54 that pierces a portion with a small thickness is set to be short, and the needle 54 that pierces a portion with a large thickness is set to be long. That is, the position of the tip of the needle 54 is set so that the tip remains inside the tip portion 22F without penetrating the tip portion 22F.

[0034] The segment without a needle 51B in the end segment 51 does not have a needle as in the segment with a needle 51A. This segment without a needle 51B is provided adjacent to the segment with a needle 51A in the circumferential direction of the drum 40 and is located between the end segment 52 in the second segment 32 and the segment with a needle 51A. The surface of the segment without a needle 51B is formed in a substantially arc shape when viewed from the axial direction of the drum 40. In the present embodiment, the substantially arc shape includes not only the case formed by a single arc but also combinations of a plurality of arcs, combinations of an arc and a straight line, and the like.

[0035] The segment without a needle 51B is supported, for example, by a guide 64 extending in the axial direction of the drum 40. The guide 64 is movable in the radial direction of the drum 40, for example, by the expansion and contraction of a cylinder device 66. When the guide 64 moves, the segment without a needle 51B also moves in the radial direction of the drum 40.

[0036] In FIGS. 3, 6, and 9, the end segment 52 in the second segment 32 is supported by, for example, two guides 68. The guides 68 are movable in the radial direction of the drum 40, for example, by the expansion and contraction of a cylinder device 70. When the guides 68 move, the end segment 52 also moves in the radial direction of the drum 40.

[0037] The end segment 52 and the segment without a needle 51B are configured to support the lower surface of the tread member 22 when the tread member 22 is wound around the drum 40. On the other hand, the central segments 41, 42 are configured not to move in the radial direction of the drum 40 except when the entire drum 40 expands and contracts. Therefore, depending on the thickness of the belt member 24 wound around the central segments 41, 42, it is possible to move the end segment 52 in the second segment 32 and the segment without a needle 51B in the first segment 31 in the radial direction of the drum 40. Thereby, it is possible to support the lower surface near the rear end portion 22R of the tread member 22 by the end segment 52 and the segment without a needle 51B.

[0038] When the needle 54 extends, the position of the stepped portion 55 is set, for example, to be constant according to the thickness of the belt member 24. That is, the position of the stepped portion 55 of the needle 54 when the tread member 22 is wound around the drum 40, the position of the needleless segment 51B in the first segment 31, and the position of the end segment 52 in the second segment 32 are configured to correspond to the position of the outermost surface of the belt member 24.

[0039] (Function) This embodiment is configured as described above, and its function will be described below. In FIG. 1, in the tire molding apparatus 1, the pressing device 10 presses the tire material 2 disposed on the tire molding drum 4 by a plurality of pressing rolls 12 in a state where the plurality of pressing rolls 12 are displaceable. The pressing device 10 individually controls the pressure of the plurality of pressing rolls 12, and each pressing roll 12 presses each part of the tire material 2 with a predetermined pressure.

[0040] When joining the ends of the tire material 2, for example, the front end portion 22F and the rear end portion 22R of the tread member 22, the tire material 2 is pressed by the plurality of pressing rolls 12 while rotating the tire molding drum 4. At this time, the pressure of each pressing roll 12 is adjusted according to the shape, shrinkage amount, or elongation amount of the tire material 2 to adjust the deformation amount of the tire material 2 by each pressing roll 12. Thereby, the end portion of the tire material 2 is formed into a target shape, and the joining amount of the tire material 2 is adjusted. Further, the pressure of the plurality of pressing rolls 12 is increased at the joint portion of the tire material 2 to surely join the tire material 2 at a high pressure. When bringing the plurality of tire materials 2 disposed on the tire molding drum 4 into close contact with each other, the air between the plurality of tire materials 2 is extruded by the pressing of the plurality of pressing rolls 12 to surely bring the plurality of tire materials 2 into close contact with each other.

[0041] Here, in FIG. 2, in the tire building drum 4 according to the present embodiment, the belt members 24 are wound around the central segments 41, 42. Further, the tread member 22 is wound around the belt members 24. As shown in FIG. 5, the width of the tread member 22 is larger than the width of the belt members 24, and the tread ends protrude from the belt members 24. In the present embodiment, the gap generated between the tread ends and the drum 40 can be filled by the needles 54, the stepped portions 55, the needleless segments 51B, and the end segments 52.

[0042] The end segment 51 in the first segment 31 has a needled segment 51A and a needleless segment 51B without needles. When the tread member 22 is wound around the drum 40, a plurality of needles 54 extend from the needled segment 51A from the radially inner side to the radially outer side and are inserted into the tip portion 22F of the tread end. Thereby, the position of the tip portion 22F of the tread end protruding from the belt member 24 in the tread member 22 can be stabilized.

[0043] When the position of the tip of the needle 54 in the radial direction of the drum 40 in the state where the needle 54 extends differs depending on the circumferential position of the drum 40, the needle 54 can be inserted along the cross-sectional shape of the tip portion 22F of the tread member 22 in the circumferential direction of the drum 40. Thereby, while securing the insertion length of the needle 54, it is possible to suppress the needle 54 from penetrating the tip portion 22F of the tread member 22. For this reason, the position and shape of the tip portion 22F of the tread member 22 can be stabilized.

[0044] At this time, as shown in FIGS. 7 and 10, the position of the stepped portion 55 of the needle 54, the position of the needleless segment 51B in the first segment 31, and the position of the end segment 52 in the second segment 32 correspond to the position of the outermost surface of the belt member 24. That is, the stepped portion 55 of the needle 54, the end segment 52 in the second segment 32, and the needleless segment 51B in the first segment 31 support the lower surface of the tread member 22.

[0045] Therefore, when the tread member 22 is wound around the drum 40, the tread end protruding from the belt member 24 can be supported by the stepped portion 55 of the needle 54, the needleless segment 51B in the first segment 31, and the end segment 52 of the second segment 32. As a result, when the rear end portion 22R of the tread end in the tread member 22 is pressed by the pressing device 10 and overlapped with the front end portion 22F of the tread end for joining, the pressing of the rear end portion 22R of the tread end can be started from the position of the second segment 32 far from the rear end portion 22R of the tread end. Further, this facilitates the stretching of the rear end portion 22R of the tread end toward the front end portion 22F side. Therefore, the rear end portion 22R of the tread end can be appropriately overlapped with and pressed against the front end portion 22F, and the two can be accurately joined.

[0046] Since the end segments 51, 52 are movable in the axial direction of the drum 40 in accordance with the widths of the central segments 41, 42 in the axial direction, they can correspond to various tire sizes and belt members 24 of various widths.

[0047] Thus, according to the present embodiment, when joining the front end portion 22F and the rear end portion 22R in the circumferential direction of the tread member 22, not only the portion of the tread member 22 supported by the belt member 24 but also the tread ends protruding from the belt member 24 can be automatically joined by the pressing device 10. Here, "automatically" means that the operation of manually overlapping the tread ends by an operator is unnecessary.

[0048] [Other Embodiments] As described above, an example of the embodiment of the present invention has been described. However, the embodiment of the present invention is not limited to the above, and it goes without saying that various modifications can be made within the scope not departing from the gist thereof other than the above.

[0049] The tire molding drum 4 may be scalable as a whole according to the size of the tire member to be manufactured.

[0050] Although the stepped portion 55 of the needle 54 is made to correspond to the position of the outermost surface of the belt member 24, the stepped portion 55 may not correspond to the position of the outermost surface of the belt member 24.

[0051] Although the end segments 51, 52 are made to be movable in the axial direction of the drum 40 in accordance with the widths of the central segments 41, 42 in the axial direction, they do not necessarily have to be movable.

Explanation of reference numerals

[0052] 2... Tire material, 4... Tire molding drum, 10... Pressing device, 22... Tread member, 22F... Tip portion, 22R... Rear end portion, 24... Belt member, 31... First segment, 32... Second segment, 40... Drum, 41... Central segment, 42... Central segment, 51... End segment, 51A... Segment with needle, 51B... Segment without needle, 52... End segment, 54... Needle, 55... Stepped portion

Claims

1. A tire molding drum for molding a ring-shaped tire member by winding a tire material around the outer peripheral surface of a substantially cylindrical drum, wherein the drum has a plurality of segments divided in the circumferential direction thereof, the segments having a first segment where the tip end portion is disposed when winding a tread member as the tire material, and a second segment where the rear end portion is disposed when winding the tread member, the first segment and the second segment each having a central segment located on the central side in the axial direction of the drum around which a belt member as the tire material is wound, and an end segment adjacent to the outside of the central segment in the axial direction, the end segment in the first segment having a plurality of needles extending from the radially inner side to the radially outer side and piercing the tip end portion of the tread member when winding the tread member around the drum, and a segment with needles having a stepped portion provided integrally with the needles and supporting the tread member when the needles extend, and a segment without needles having no needles, wherein the end segment in the second segment and the segment without needles in the first segment are configured to support the lower surface of the tread member when winding the tread member around the drum. A tire molding drum.

2. The tire molding drum according to claim 1, wherein the position of the stepped portion of the needles, the position of the segment without needles in the first segment, and the position of the end segment in the second segment when winding the tread member around the drum correspond to the position of the outermost surface of the belt member.

3. The tire molding drum according to claim 1, wherein the position of the tip ends of the needles in the radial direction of the drum in a state where the needles extend varies depending on the circumferential position of the drum.

4. The tire molding drum according to claim 1, wherein the end segment is movable in the axial direction in accordance with the width of the central segment in the axial direction of the drum.

Images